$2.$ The pasta making process can be described by the following activities: Mix the dough $($assume this takes $10$ minutes$)$; Let the dough rest $($assume this takes $20$ minutes$)$; Roll the dough $($assume this takes $5$ minutes$)$; Cut the dough into noodles $($assume this takes $10$ minutes$).$ The bottleneck of the process is the $`$let the dough rest' activity. $(2$ m a r k s $)$